Layer Experiment Overview

Core concepts

The ABC platform's layer-and-domain architecture:

Node type	Description
Global Domain	The root of the entire tree, representing 100% of the project's traffic.
Domain	A logical partition of traffic; can be nested. Each domain receives a certain percentage of traffic from its parent.
Multi-Layer Domain	Multiple layers within the domain share the same traffic pool and run in parallel; experiments within are not mutually exclusive.
Exclusive Layer	Experiments within the layer are mutually exclusive — a given user will match at most one experiment in the layer.

Traffic isolation principles

The layered architecture achieves traffic isolation between experiments through the following mechanisms:

Mutual exclusion within a layer

Within the same Exclusive Layer, each experiment occupies a distinct bucket range. Users are assigned to a unique bucket based on a hash value, so they match at most one experiment in that layer.

Orthogonality across layers

Different layers use independent hash seeds for traffic assignment. A user's variant assignment in Layer A does not affect their assignment in Layer B. The effect of experiments in the two layers can be measured independently without interference.

Result:

• Same layer → isolated (no cross-contamination)
• Across layers → independent (can be evaluated simultaneously)
• Overall effect: avoids traffic conflicts while maximizing traffic reuse

Prerequisites: configure Layers & Domains

Before creating a Layer Experiment, you need a layer to run it on.

1. Open the Layers & Domains list

Click Experiments in the left navigation bar → switch to the Layers & Domains tab.

The page displays all nodes in the current project as a table:

Column	Description
Name	Node name (indented to show parent-child relationships).
Experiments	Experiments associated with this node.
Type	Node type: Domain / Multi-Layer Domain / Exclusive Layer.
% of global traffic	Percentage of global traffic this node holds.
Buckets	Bucket range, e.g. [1~100].
Owner / Created at	Creator and creation time.

2. Enter edit mode

Click the Edit button in the top-right corner of the list page to enter the edit view.

The edit view is divided into three areas:

• Left panel: Tree navigation showing the full hierarchy under Global Domain; nodes can be expanded or collapsed. A search box at the top lets you find nodes by name.
• Center: Traffic visualization showing each node's traffic allocation as a bar chart. Each node card displays % of parent traffic and % of global traffic.
• Bottom legend:
  • Used — traffic already occupied by experiments
  • Unavailable — traffic that cannot be allocated
  • Available — remaining traffic available for new experiments

3. Add to Layers & Domains

Click the + Add button in the top-left corner. An Add to Layers & Domains panel slides out on the right:

Field	Description
Name	Node name (e.g. "game_strategy_layer").
Key	Unique identifier; can only contain letters, numbers, and underscores.
Parent Domain	Select the parent domain (dropdown shows all selectable domains).
Type	Node type (available options depend on the selected Parent Domain; see rules below).
Configure traffic	Percentage of traffic allocated to this node (slider).
Parameters (optional)	Set default parameters for this node (only available for Exclusive Layer type).
Description (optional)	Node description.

Type selection rules

Parent node	Available types	Notes
Global Domain	Domain	Only sub-domains can be created under the global domain as the first level of traffic partitioning.
Other Domain	Domain / Multi-Layer Domain / Exclusive Layer	A sub-domain can be further partitioned or turned directly into an experiment layer.

Type	When to use
Domain	When you need multi-level traffic partitioning, e.g. first by business line, then by feature module.
Multi-Layer Domain	When multiple experiments have no parameter conflicts and you want to reuse the same traffic pool to run experiments faster.
Exclusive Layer	When experiments have parameter conflicts or require strict isolation, so a given user matches only one experiment.

Configure traffic

A slider control that sets the percentage of traffic this node can use.

Notes:

• The available range depends on the unused traffic remaining in the parent domain.
• If all traffic in the parent domain has already been allocated to other sibling nodes, the slider cannot be adjusted (shows 0).
• If the slider cannot be dragged, check:
  1. Whether a Type has been selected (the slider cannot be adjusted before a Type is chosen)
  2. Whether the parent domain still has remaining available traffic

Parameters

Parameters can only be configured when the Type is Exclusive Layer.

Steps:

1. Click Add parameter.
2. Fill in Parameter key, Value type (String / Number / Boolean / JSON), and Parameter value.
3. To add more parameters, click Add parameter again.
4. Click Confirm when done.

When no default parameters are configured for the node, the system uses policy ID 100000 as the default policy.